1. Technical Field
The present invention relates to an illumination device, an image display device, and a projector.
2. Related Art
Projection type image display devices (projectors) are conventionally known.
A projection type image display device uses a projection system to project colored light, which contains image information generated by a spatial light modulation device such as a liquid crystal device, onto a screen.
In a projection type image display device, as disclosed in Japanese Unexamined Patent Publication, First Publication No. H11-64789 and Japanese Unexamined Patent Publication, First Publication No. 2000-162548, a technique of using laser light as a light source is proposed.
In such a projection type image display device, an incidence face of the spatial light modulation device must be illuminated by laser light with uniform illuminance distribution.
When using a predetermined optical system to realize uniform illuminance distribution, there is concern that a desired image may not be obtained due to the positional relationship between the laser light and the optical system.
Furthermore, depending on the configuration of the optical system, there is concern that the device will become larger and more complex, or that its cost will increase.
Depending on the configuration of the optical system, there is also concern that the light utilization efficiency will decrease.
In order to obtain a desired image in a projection type image display device, it is important to illuminate the incidence face of the spatial light modulation device with laser light of uniform distribution.
Therefore, it is important to construct an optical system for illuminating the incidence face of the spatial light modulation device with laser light of uniform distribution.